Just How Dangerous is Radiation from CT Scans?

Coming to the ER with a headache and no prior migraine history?  You can probably expect a head CT.  Belly pain?  That’ll probably warrant imaging as well.  Just how much radiation are our patients getting with an average CT scan?  What effect will this have on their future health?

In 2009, the FDA published a Radiation Dose Comparison identifying the exact amount of radiation exposure from the average dental X-Ray to a CT scan of the abdomen.  According to the FDA, a CT scan of the abdomen exposes the patient to an amount of radiation 400 times that of a chest X-Ray.  This amount equates to an astounding 2.7 years worth of the level of radiation naturally experienced in the environment.

Some experts argue the FDA is wrong.  They believe radiation exposure is even higher with your average CT.  Experts argue that rather than the 8 mSv of radiation the FDA reports with an abdominal CT, patients are actually exposed to an average of 31 mSV, equivalent to nearly 1600 chest X-Rays.  Obese patients are at even greater risk of radiation exposure with imaging procedures as higher levels of radiation are necessary to obtain clear films.  90 mSv of radiation, the exposure level reached with some abdominal CT scans, is equal to the background radiation of living for over a 30 year period.  All this in a procedure lasting minutes.

Just how much cancer are all these CT scans causing?  Last week, the New York Times reported that CT scans provide three-fourths of American’s radiation exposure accounting for 1.5 percent of all cancers in the United States.  Dr. Rebecca Smith-Bindman, a radiology specialist, reported that “More than 10 percent of patients each year are receiving very high radiation exposures”.  A 2009 study published in the Archives of Internal Medicine attributed 29,000 future cancers caused by the 70 million CT scans performed annually in the United States.  The article calculates that an astonishing one out of every 270 forty year-old women undergoing CT angiography will develop cancer related to the procedure.

These studies place us as medical providers in a sticky situation.  CT scans offer unprecedented aid in diagnosing our patients.  They provide clarity in situations of uncertainty and help prevent misdiagnosis.  Some providers see CT scans as the key to preventing a medical malpractice lawsuit.  And, well, for others they are simply ordered as a substitute for a good ‘ole physical exam.  The tension between the risk and benefit of CT scans is high and must not be taken lightly.  Order with caution.

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